1. Field of the Invention
The present invention relates generally to pointing devices, and more particularly to a pen-type mouse device.
2. Description of the Related Art
A conventional mouse is operated in such a way that a cursor is moved or a click operation is performed by a user moving a mouse on a plane, such as a mouse pad, to rotate a ball of the mouse.
Further, an operation can be carried out using a pen-type mouse instead of a conventional mouse. A pen-type mouse is formed in a pen shape to allow the operation of the mouse to be similar to a handwriting operation of a human being, thus further facilitating the operation of the mouse.
Generally, a pen-type mouse is operated in such a way that a tablet, such as a digitizer, recognizes that the pen-type mouse approaches or comes into contact with the tablet.
Further, the movement of a cursor is not performed by moving the pen-type mouse while bringing the pen-type mouse into contact with the tablet, but performed by moving the pen-type mouse on the tablet in a non-contact manner while spacing apart from the tablet by a certain distance (typically, 1.5 cm). Therefore, it is inconvenient to move the pen-type mouse, that is, move the pen-type mouse while spacing apart from the tablet by a certain distance. A user develops discomfort at his or her wrist even though the user only gently uses the pen-type mouse. Such an inconvenience becomes a weak point in a recent trend toward the rapid increase of the utilization of a computer and a mouse.
Further, in order to implement a pen-type mouse using a conventional ball mouse, the size of a ball must be decreased. However, as the size of the ball is decreased, the sensitivity of the mouse movement is greatly decreased. Therefore, it is difficult to maintain the sensitivity of the conventional mouse from a mechanical perspective. That is, most pointing devices using a ball employ a method of recognizing the rotation of a ball through a pinion gear. However, as the size of a ball is decreased, driving force capable of rotating the pinion gear is decreased. Therefore, since the pointing sensitivity and precision of the mouse is decreased, such a ball mouse is not suitable for the pen-type mouse.
Further, a pen-type mouse produced in a conventional optical image manner is problematic in that, as the slope of the mouse varies, a distance between an image sensor and a plane varies to deviate a focus, thereby preventing the operation of the mouse from being recognized.
Further, as a method of implementing a pointing device using a conventional pen-type optical device, there is a method of reducing the size of a lens to increase a depth (a focal distance to a location where an image of an object is formed is increased by reducing the size of an iris of a lens in a camera) and maintaining a certain distance from an image using a ball-point pen or tip point sharply projected from the front of the device, thus solving a problem of image distortion of an object due to the slope of the pointing device according to a pointing operation in some degree. However, this method enables a pointing function on only a plane on which a uniform pattern is formed (a paper or mouse pad on which a pattern is printed).